140CPU43412A Hot Standby

You cannot create a Quantum Hot Standby configuration running one 140CPU53414A PLC with Unity firmware and one with NxT firmware. When using an NxT configuration in hot standby, both PLCs must have NxT firmware. When using a Unity Quantum hot standby configuration, only specific hot standby controllers can be used. The 140CPU43412A and 140CPU53414A PLCs are not supported in Unity Hot Standby configurations.